<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- hhhh -->
    <script>


        // 单行注释


        /*
        多
        行
        注
        释
        */
// 多写注释,代码整洁,低耦合高内聚,代码规范
        document.write("1111");
        document.write("1111");
//单行作用域:分号,多句区间{}

let num = 99;


        {
            console.log(num)
            let num1 = 1;
        }
        console.log(typeof num)

//{}自降一辈
       


        
    </script>
</body>
</html>